Turbine Engine Operation, Instuments, Maintenance + Overhaul Flashcards
Why are compressor washes performed and what methods are commonly used?
To remove any contaminants from the compressor section and to improve engine performance.
Fluid wash.
Abrasive grit wash
How can you tell if a turbofan or turbojet engine is out of trim?
There will be high EGT’s at the target EPR for takeoff power.
Name the different types of compressor blade damage that may be found during inspection:
Dents.
Cracks.
Galling.
Pitting.
Scratches.
Burrs.
Burns.
Gouges.
What kind of markers can be used to mark the parts in hot and cold sections during repair?
Layout dye.
Felt tip marker.
Chalk.
How does relative humidity affect turbine engines?
Negligible effect
What criteria determines replacement of life limited turbine engine components?
Cycles.
Hours.
Calendar time.
If turbine blades are removed from a turbine disk, why should they be reinstalled in the same location?
To maintain the balance of the turbine wheel.
How are gas turbine engine tachometers calibrated?
They are calibrated in percent RPM.
On a turbine engine what is the engine pressure ratio and what does it indicate?
It is the ratio between the total inlet pressure and the total turbine exhaust pressure.
It indicates the thrust developed by the engine.
On a turbine engine, what does exhaust gas temperature indicate and how is it obtained?
EGT is the average temperature of the turbine discharge gases.
It is obtained by thermocouples placed near the turbine exit.
Can the EGT system on a turbine engine be checked without running the engine?
Yes, by checking the resistance of thermocouples and circuits.
What are the possible causes for a turbojet or turbofan engine having high EGTs, low RPMs, and high fuel flow at all engine pressure ratios?
Turbine damage or loss of turban efficiency due to wear.
